This invention relates generally to apparatus and a method for extruding an elongated article having at least one spiral profile along the length of said elongated article; and further includes the extruded thermoplastic foam rod produced thereby having at least one helical profile along the length thereof.
In the extrusion process a plastic resin melt is formed under heat and pressure. The melt is usually formed continuously by a rotating screw in a barrel which converts solid pellets of the resin or plastic into the flowable or extrudable material. A wide variety of additions may be incorporated into the extrudable material such as extenders, blowing agents, fire retardants, pigments and such.
Such extruder generally includes a hopper through which the extrudable material is introduced into the extruder, heating element to melt the extrudable material and a nozzle or opening from the extruder for communicating the extrudable material from the extruder to a die. The die may generally include a plenum chamber which then communicates with the die opening.
Various extruders and methods have heretofore been produced.
For example, U.S. Pat. No. 5,316,460 generally relates to synthetic resin material feeding apparatus for use in a system for forming a sealing liner on the inner surface of a top panel wall of container closure shelf which has an extruder and a gear pump. The driving mechanism the extruder and the gear pump have an intermittent rotation-driving output for intermittently operating the extruder and the gear pump.
Moreover, U.S. Pat. No. 5,401,454 generally illustrates an extrusion die and flow control method which incorporates a flow control in the form of a flow diverter which extends traversely across the flow path. The diverter forms part of a window upstream of the die lips and provides a slight tapering enlargement which may be moved along the window across the flow path from one side to the other or preferably from the center symmetrically outwardly or vice versa to divert flow from the center proportionally to the edges without changing the total cross-sectional area of the window.
Moreover, some of the prior art extruders included a rotational movement, however, none of such prior art extruders produce an article having at least one spiral profile along the length thereof.
For example, U.S. Pat. No. 4,832,588 teaches that material is threaded out into a space between a worm and a nozzle but since the nozzle core is locked against rotation the frictional engagement between the material and both the outer surface of the nozzle core will cause the material to stop rotating as it is forced further towards the nozzle.
Moreover, U.S. Pat. No. 5,505,887 illustrates rotating a portion of a die in a first rotational direction and rotating a mandrel in a second rotational direction so as to enhance helical fibrous formation of tubing material.
It is an object of this invention to provide an improved apparatus and method for producing elongated articles having a rotational profile.
It is an aspect of this invention to provide apparatus for extruding an elongated article comprising a die having an opening therethrough; an extruder for discharging extrudable material through said die opening; structure for rotational movement between said die and said extruder so as to produce said elongated article having a rotational profile.
In accordance with yet another aspect of the invention, to provide apparatus for extruding an elongated article having at least one spiral profile along the length thereof comprising a die having an opening; an extruder for discharging extrudable material through said die opening; structure for rotational movement between said die and said extruder so as to produce said elongated article having at least one spiral profile along the length of said elongated article.
It is another aspect of this invention to provide a method of producing an elongated foam rod having at least one helical profile along the length of said rod comprising a rotating a die opening relative to an extruder; selecting the die opening so as to impart the helical profile along said length of said foam tube.
It is another aspect of this invention to provide an extruded thermal plastic rod having at least one helical profile along the length thereof.